1. Field of the Invention
The present invention relates to a radiation cassette carrier for providing portability to a radiation cassette and portable radiation imaging apparatus using the radiation cassette carrier.
2. Description of the Related Art
Generally, apparatuses that obtain an X-ray image by irradiating a target object with X-rays and detecting the intensity distribution of X-rays that have been transmitted through the target object are widely used in the field of industrial nondestructive testing and medical diagnosis. General methods of imaging include the film/screen system and the CR (Computed Radiography) system. In these systems, a photosensitive film or a phosphor plate that stores an image as a latent image is placed in a housing case called a cassette, which is standardized by JIS Z 4905, and used in image-taking. When taking an image, an operation for aligning the target object and the cassette in a desired position is necessary, but the cassette has a rectangular parallelepiped shape, and no particular consideration is given to how a user will hold the cassette. Therefore, as disclosed in Japanese Patent Laid-Open No. 10-282598 (hereinafter referred to as “Patent Document 1”), a cassette carrier has been proposed that stores a cassette in a central portion thereof and has handle portions on both sides.
Meanwhile, a DR (Digital Radiography) system has been also proposed in which an X-ray image is captured and digitalized using a semiconductor sensor, and the size and weight of apparatuses have been reduced with improvements in packaging technology, resulting in commercialization of portable X-ray imaging apparatuses. However, since such apparatuses incorporate a large number of electronic components, they are heavier than conventional cassettes. Accordingly, as disclosed in Japanese Patent No. 3577003 (hereinafter referred to as “Patent Document 2”), an apparatus in which a handle portion for holding is formed in the casing of an x-ray detection portion has been developed.
When taking an x-ray image in a medical setting, various platforms such as a platform for use in the upright position or a table for use in the lying position are used for positioning and holding the cassette with respect to a subject. Many of these platforms that are installed are designed in conformity with the external shape of the cassette standardized by JIS Z 4905. If the shape or size of an X-ray detection portion utilizing the DR system is different from the size of the standardized cassette, a new platform will be needed to match the DR X-ray detection portion, which increases the investment costs. Therefore, provision of an X-ray imaging apparatus compatible with the external shape of the cassette specified by JIS Z 4905 has been desired. Due to advancement in high-density packaging technology and wireless technology, X-ray imaging apparatuses having a shape compatible with the standardized cassette have been developed. However, on the other hand, the portability taken into account with conventional DR apparatuses is compromised, and a cassette carrier such as disclosed in Patent Document 1 becomes necessary.
With a configuration for housing a cassette as disclosed in Patent Document 1, wireless communication performance is degraded, and thus measures that take account of wireless communication performance are necessary. Also, it may no longer be possible to access to a wired connection portion or an operation portion provided in the cassette. It is conceivable to provide a relay cable or a connector in the cassette carrier, and enable wired connection to the stored cassette. However, when connection is established through a relay cable of the cassette carrier, EMC (electromagnetic compatibility) may deteriorate or the external size of the cassette carrier may increase. Furthermore, in Patent Document 2, a handle is formed in the casing, and thus although it is easy to achieve a design that can bear the strength load applied when positioning the imaging portion with respect to the subject, the design will deviate from external shape of the standardized cassette.